Keep writing! It’s as simple and as difficult as that.
Honestly, people often say to me, “Oh, I want to be a writer but I don’t think I’m good enough.” My response is usually along the same lines as I give my students: if you don’t make mistakes, you’ll never learn how to improve.
I remember back when I was fourteen or fifteen, and I was writing ALL the time. Every day, way into the wee hours. I loved it. I felt so free. I was liberated. It wasn’t until my self-confidence cracked that I stopped. For years, my work stagnated because I didn’t write.
So my advice to new writers? Keep writing. Make mistakes. Write things you aren’t satisfied with. It’s only when you re-read and find the errors that you truly learn and grow.